The Childhood Leukemia International Consortium (CLIC), established in 2007, is a group of independent, international researchers who study the role of environmental, genetic, infectious, and clinical risk factors in the etiology of childhood leukemia and who share data from case-control and family-based trio studies. CLIC includes 33 childhood leukemia case-control studies worldwide from 17 countries (25 Principal Investigators) representing approximately 20,000 cases and 200,000 controls. Approximately 90% of the studies have comprehensive epidemiologic data, and about half have biospecimens. CLIC is expanding its research portfolio to include childhood cancers other than leukemia, which will enable the Consortium to pool resources and data across 16 other childhood cancers (e.g., 12 studies on intracranial tumors, 11 studies on astrocytoma, 10 studies on ependymomas, 8 studies on medulloblastomas, 9 studies on other gliomas, and 9 studies on both Hodgkin and non-Hodgkin lymphomas, etc.). Though CLIC members participate in teleconferences throughout the year, the annual in-person meeting for members is essential for planning and evaluating progress on collaborative research projects, and discussing new research directions. The next three CLIC annual meetings (2015-2017) will provide a forum for continuing discussions and increasing the knowledge base of members. It will also achieve the following goals: * Plan and conduct genetic and gene-environment pooled and validation studies in childhood leukemia; discuss future epigenetic studies. * Discuss expanding CLIC to include other childhood cancers, especially brain tumors, which will take advantage of our existing infrastructure, collegial relationships, and knowledge; evaluate current literature to identify gaps in research where CLIC can best contribute. * Identify and address methodological challenges such the impact of possible selection and recall bias, application of statistical methods for causal inference. * Partner with leading national institutes of health to identify potential studies of under-represented children with cancers; encourage participation and increase membership of under-represented populations from Central and South America and Asia. * Discuss and identify research areas most suitable for quantitative research translation, research dissemination and communication to stakeholders.